Farm Workers Contracting Drug-resistant Bacteria, Study Shows

Workers at industrial livestock plants where animals receive antibiotics have developed drug-resistant bacteria in their noses, according to a new study.

The bacteria include Staphylococcus aureus, commonly known as "Staph," which include the well-known bug MRSA (methicillin-resistant Staphylococcus aureus). The study showed that not only were the bacteria found in the noses of the workers resistant to methicillin, but other antibiotics as well. The researchers tested for genetic markers to indicate the bacteria came from livestock.

The study, conducted by researchers at the Johns Hopkins Bloomberg School of Public Health and others, adds to a four-decades-old debate over the use of antibiotics at industrial farms. The new research, published July 2 in the journal PLOS ONE, focused on workers at industrial livestock plants and well as antibiotic-free farms in North Carolina.

North Carolina ranks second nationally behind Iowa in terms of hog production. The study showed the bacteria present in the noses of the industrial workers, but not in those who work on antibiotic-free farms.

Dr. Christopher Heaney, a professor at Johns Hopkins, told Healthline the debate over antibiotic use in livestock production has raged since a 1976 study. That research showed development of tetracycline resistance in coliforms isolated from the feces of chicken farmers who raised birds that were given the drug in their feed.

“A limitation of our study is that it did not sample animals on the farm,” Heaney said. “However, it does provide information that could contribute to a discussion about antibiotics use in livestock production.”

Bacteria, but Not Infection

Despite the presence of the bacteria, the workers did not have full-blown infections.

“Whether or not these drug-resistant livestock associated strains of [Staph]pose a health risk to workers still needs to be investigated,” Heaney said. “Studies designed to assess the occurrence of [Staph] infections among livestock workers would need to be conducted to advance understanding about the potential health implications of nasal carriage. In clinical settings, nasal carriage has been shown to increase the risk of subsequent infection, but the state of knowledge about risks that nasal carriage may pose to livestock worker health is limited.”

'An Important Public Health Concern'

In the study, researchers noted that livestock raised in industrial settings commonly are given antibiotics to stimulate growth. In a statement to Healthline, the U.S. Food and Drug Administration, or FDA, denounced this practice.

“The health of animals and people are undeniably interconnected in today’s world,” the statement read. “All uses of antimicrobial drugs, by humans and livestock producers, contribute to the development of antimicrobial resistance, an important public health concern.”

The statement continued, “These important drugs must be used judiciously to slow the development of resistance in both animal and human medicine. Using medically important antimicrobials to increase growth or production in food-producing animals is not a judicious use.”

Meanwhile, US. Rep Louise Slaughter (D-N.Y.) has introduced the Preservation of Antibiotics for Medical Treatment Act, or PAMTA, which is designed to stop the overuse of antibiotics on the farm. In a statement to the news media, she called on the FDA to do more.

“Not only are we frittering away one of the greatest medical miracles of all time—the antibiotic—but we are failing in our basic duty of protecting the health and lives of Americans. Every new study that confirms the public health threat from antibiotic overuse in American livestock makes the FDA’s hands-off approach more indefensible. If the FDA won’t protect Americans, then Congress has to step up to the plate by passing my bill to stop the overuse of antibiotics in food-animals,” the statement said.

Dr. Jennifer Koeman, the National Pork Board's director of producer and public health, told Healthline the organization offers guidelines to pork producers about the responsible use of antibiotics.

“What we want to do is be able to offer consumers and producers the opportunity to produce the way they would like to produce and have the consumer be able to have that choice,” she said. “Some have that choice and some don't, depending on how much they have to spend.”

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